Telecommunication systems, cable television systems, and data communication networks use optical networks to rapidly convey large amounts of information between remote points. In an optical network, information is conveyed in the form of optical signals through optical fibers. Optical fibers comprise thin strands of glass capable of transmitting optical signals over long distances with very low loss of signal strength.
In recent years, the use of telecommunication services has increased dramatically. As the demand for telecommunication services continues to grow, optical networks are quickly becoming overburdened by the increasing amount of information communicated over such networks. The addition of new networks or the expansion of existing networks may however be too costly to be practical solutions to this problem. Thus, efficient use of network resources has become an important goal in developing and operating optical networks.
Optical networks often employ wavelength division multiplexing (WDM) or dense wavelength division multiplexing (DWDM) to increase transmission capacity. In WDM and DWDM networks, a number of optical channels are carried in each fiber at disparate wavelengths. Network capacity is based on the number of wavelengths, or channels, in each fiber and the bandwidth of the channels. By using WDM add/drop equipment at network nodes, the entire composite signal can be fully demultiplexed into its constituent channels and switched (added/dropped or passed through).
In WDM and DWDM networks, traffic from one network node to another network node is often assigned to a particular wavelength on which the traffic is communicated over the network. By assigning different traffic streams to different wavelengths, interference between different traffic streams is prevented. However, in certain situations, this creates inefficiency in the network. For example, if the traffic from a node that is assigned a particular wavelength does not typically use much of the bandwidth (capacity) associated with the wavelength, then inefficiencies are created.
The use of optical light trails has been proposed to address these inefficiencies. A light-trail is a generalization of a light path (an optical wavelength circuit), where multiple nodes along the path can take part in communication along the path. Thus, a light-trail enables a plurality of nodes included in the light-trail to share the use of an optical wavelength to transmit traffic between the nodes included in the light-trail. Besides addressing some of the inefficiencies discussed above, light-trail communications may also allow optical multicasting and dynamic provisioning.
Although light-trails have been proposed as efficient solutions to some optical networking inefficiencies, a need remains for efficient and reliable optical component configurations to implement light-trails in particular optical networks.